HHMI's Holiday Lectures on Science
The Howard Hughes Medical Institute is a philanthropy that supports biomedical research and science education. As part of its mission to strengthen science education, the Institute presents the Holiday Lectures on Science, an annual series that brings the latest developments in a rapidly moving field of research into the classroom.
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2007 HIV/AIDS Lecture 1
"From Outbreak to Epidemic" by Bisola O. Ojikutu, M.D., M.P.H. In 1981, an obscure and deadly disease surfaced. Previously healthy homosexual men in the United States began arriving at clinics with rare cancers and infections usually seen in people with weakened immune systems. Most of them died. Th ...
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2007 HIV/AIDS Lecture 2
"AIDS and the HIV Life Cycle" by Bruce D. Walker, M.D. The first AIDS cases healthy young men with multiple infections and cancers???were a mystery to even the most seasoned physicians. The symptoms pointed to a major defect in the immune system. Further investigation found swollen lymph nodes, anot ...
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2007 HIV/AIDS Lecture 3
"Drugs and HIV Evolution" by Bisola O. Ojikutu, M.D., M.P.H. In 1987, four years after HIV was identified, the Food and Drug Administration (FDA) approved the use of azidothymidine (AZT) to slow the progression of HIV infection to full-blown AIDS. AZT targets reverse transcriptase, an enzyme essenti ...
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2007 HIV/AIDS Lecture 4
"Vaccines and HIV Evolution" by Bruce D. Walker, M.D. The global HIV epidemic continues to spread: 40 million people are infected worldwide. While drugs are essential in the battle against HIV, a vaccine would be a major advance. A vaccine, for example, can be preventive and does not require frequen ...
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2007 HIV/AIDS Discussion 1
"Students fighting the HIV epidemic" A 90-minute discussion session with the lecturers, Washington, D.C.-area high school students, and three students???Piali Mukhopadhyay, Shefali Oza, and Stella Safo???who are helping in the global fight against HIV and AIDS.
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2007 HIV/AIDS Discussion 2
"Living with HIV" A 90-minute discussion session with the lecturers, Washington, D.C.-area high school students, and three HIV-positive individuals???Adam Barrett, Zinhle Thabethe, and Phill Wilson???who share their personal experiences about living with HIV.
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2000 Biological Clocks Lecture 1
"Biology in Four Dimensions" by Joseph S. Takahashi, Ph.D. After describing the fundamental properties of circadian rhythms, Dr. Takahashi takes us on an exciting journey into a very special region of the brain???the suprachiasmatic nucleus (SCN). The SCN functions as a "master" biological clock tha ...
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2000 Biological Clocks Lecture 2
"Unwinding Clock Genetics" by Michael Rosbash, Ph.D. Dr. Rosbash reveals that the fruit fly (Drosophila melanogaster) has a biological clock in its nervous system. Although tiny in size, the fruit fly has had a major impact on our understanding of circadian rhythms. The fruit fly served as the instr ...
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2000 Biological Clocks Lecture 3
"PERfect TIMing" by Michael Rosbash, Ph.D. Dr. Rosbash discloses how scientists have persuaded Mother Nature to reveal the inner workings of the fruit fly's biological clock. From the almost 14,000 genes in this organism, scientists have painstakingly identified a handful that regulate the "ticktock ...
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2000 Biological Clocks Lecture 4
"The Mammalian Timekeeper" by Joseph S. Takahashi, Ph.D. Dr. Takahashi describes the powerful strategies that he and others have harnessed for understanding biological clocks in mammals. To tease out the secrets of how the clocks in higher organisms function, scientists had to overcome uncommonly hi ...
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2001 Sex Determination Lecture 1
"Deciphering the Language of Sex" by David C. Page, M.D. Is it a boy or a girl? Dr. Page looks at how we define male and female and summarizes the development of human sex characteristics. He then explains the role of the sex chromosomes, X and Y, and, in particular, the SRY gene. Dr. Page demonstra ...
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2001 Sex Determination Lecture 2
"Hermaphrodites: The Safer Sex" by Barbara J. Meyer, Ph.D. Dr. Meyer explains the value of studying model organisms and introduces the nematode C. elegans Affectionally known as "the worm," it has two sexes: male, which possesses a single X chromosome, and hermaphrodite, which possesses two X chromo ...
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2001 Sex Determination Lecture 3
"Sex and Death: Too Much of a Good Thing" by Barbara J. Meyer, Ph.D. Having too many chromosomes can lead to too much gene expression. If a male and a female have a different number of X chromosomes, a dosage-compensation mechanism is necessary to equalize the level of gene expression. In human fema ...
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2001 Sex Determination Lecture 4
"Sexual Evolution: From X to Y" by David C. Page, M.D. Dr. Page interprets the results of an audience-participation experiment comparing testosterone levels in males and females of varying ages. He then explains how the Y chromosome is inherited from father to son in a near clonal fashion. He demons ...
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1995 RNA Lecture 1
"Catalysis, Chemical and Biochemical" by Thomas R. Cech, Ph.D. Life processes are fundamentally chemical reactions. Left to themselves, however, the reactions would occur too slowly and nonspecifically to sustain life. Cellular enzymes are catalysts that tame reactions by accelerating them, lending ...
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1995 RNA Lecture 2
"RNA as an Enzyme: Discovery, Origins of Life, and Medical Possibilities" by Thomas R. Cech, Ph.D. Discovery of RNA's catalytic activity led to unexpected spin-offs, including a new scenario for the origin of life. In a different area, the ability of RNA catalysts (ribozymes) to cut and splice RNA m ...
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1995 RNA Lecture 3
"How to Accelerate a Reaction 100,000,000,000 Times Using Only RNA" by Thomas R. Cech, Ph.D. RNA and protein are built from different chemical units and assembled in distinct ways. Thus, the ability of RNA to exhibit catalytic activity rivaling that of traditional protein enzymes was unexpected. Stu ...
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1995 RNA Lecture 4
"Life at the End of the Chromosome: Another RNA Machine" by Thomas R. Cech, Ph.D. Chromosomes of humans and other eukaryotes contain linear DNA molecules. The chromosome ends, or telomeres, are necessary for DNA stability and replication. Telomere replication is carried out by telomerase, whose RNA ...
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1999 Infectious Diseases Lecture 1
"Microbe Hunters: Tracking Infectious Agents" by Donald E. Ganem, M.D. How are diseases recognized as infectious and how are their causes identified? In this lecture, Dr. Ganem describes how epidemiologists, physicians, and microbiologists work together to identify and study pathogens. He first expl ...
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1999 Infectious Diseases Lecture 2
"The Microbes Strike Back" by B. Brett Finlay, Ph.D. Dr. Brett Finlay explains why bacterial diseases continue to be a major health problem worldwide, causing a third of the world's deaths every year. After describing how bacteria grow, reproduce, and spread, Dr. Finlay explains how antibiotics work ...
HHMI's Holiday Lectures on Science
